David Burnham, author of the book A Law Unto Itself: The IRS and the Abuse of Power, has written that presidents back to at least Herbert Hoover have made questionable use of the organization.
Burnham and historians have accused President Franklin Delano Roosevelt of having the IRS look into a number of his critics, including Sen. Huey Long, Father Charles Coughlin and Hoover Treasury Secretary Andrew Mellon. (Long may have been planning to challenge Roosevelt in 1936, but was assassinated a year before the election.)
Susan Long — who along with Burnham is co-director of the Transactional Records Access Clearinghouse at Syracuse University — said Nixon created a broad, systematic political use of the IRS, rather than use the agency on a case-by-case basis.
"It was a whole program — an 'enemies list' — that the IRS had," Long said.